Question

How did the belief in logic and reason promote the beginnings of the social sciences?

Answer 1

Thru: Humanism
The humanism philosophy was what developed during the renaissance is associated with a shift in focus away from religious subjects toward more secular subjects. Humanism focused on the man, himself and woman, herself. This humanistic philosophy focused on the value of emergence of human beings, as one highest form of animals in the kingdom and has the capacity and capability of “reason”. Logic is the philosophical study of logical reasoning which humans beings are able to do, evolutionarily with their neo-cortex.   

Moreover, the development of understanding human beings lead to the belief and study of them in relation. Since then science was introduced because of humanism that lead to logic and reason stating humans as capable of knowledge and intellectuality that lead scientists to study how these creatures, humans respond and mechanises.  Hope this helps!!